// 错误示例
class user {
  username: string;

  constructor(username: string) {
    this.username = username;
  }

  sayHi() {
    console.log("hi" + this.username);
  }
}

// 枚举名
enum userType {
  TEACHAR = 0,
  STUDENT = 1,
}

// 命名空间
namespace base64Utils {
  function encrypt() {
    // ...
  }

  function decrypt() {
    // ...
  }
}

// 正确示例
class User {
  username: string;

  constructor(username: string) {
    this.username = username;
  }

  sayHi() {
    console.log("hi" + this.username);
  }
}

// 枚举名
enum UserType {
  TEACHAR = 0,
  STUDENT = 1,
}

// 命名空间
namespace Base64Utils {
  function encrypt() {
    // ...
  }

  function decrypt() {
    // ...
  }
}
